cargo tie-downs (also called "hold-downs" or "lashing straps") are well known. These devices typically include a strap, cord or band having a hook or loop at each end which enables the device to be connected to appropriate structure on a vehicle (or trailer). The strap, cord or band is tensioned across the load to secure the load to the vehicle. Some of these devices are elastic (e.g., a "bungee cord"), while others are substantially inelastic and include a ratchet, gear set, or buckle which allows the length of the strap to be varied to secure the load on the vehicle.
One type of ratchet tie-down device is available from the assignee of the present invention under the mark/designation 46259 Heavy Duty Tie-Down. This device includes a strap having a first hook at one end, and a handle or loop at the other end. The strap extends around a block (i.e., a bar or rod) located within a buckle, which itself is connected by a short strap to a second hook. The first and second hooks can be secured to appropriate structure on the vehicle or trailer and the handle/loop can be pulled by the user to tighten down the strap. The buckle includes a locking ratchet with teeth which grab the strap and prevent the strap from slipping around the block while in its tightened position. A finger button on the buckle can be manipulated to disengage the locking ratchet from the strap and allow the strap to be released or lengthened.
Applicant believes that the above-described devices, such as the ratchet tie-down device, typically only use a single ratchet, gear set or buckle to vary the length of the strap. While the single ratchet, gear set, or buckle can be effective for securing some loads on a vehicle, in some situations it can be desirable to have additional tension on the load which cannot be achieved using these devices. This is in part believed due to the known devices not providing a mechanical advantage to the strap when tightened. The single buckle, gear set or ratchet only has a single block for the strap between the end hooks, and otherwise does not increase the user's mechanical advantage during the tie-down process (i.e., these devices have a 1:1 mechanical advantage). Moreover, some of these devices, and in particular the ratchet-type devices, actually have a decreasing mechanical advantage as the device is being tightened, which makes it even more difficult to tighten the device as the strap is pulled.
Accordingly, applicant believes that there is a demand in the market for a tie-down device having a mechanical advantage which can be easily and effectively tightened down over a load such that the load can be securely fastened to a vehicle or trailer.